Renal function and intrarenal hemodynamics in acutely hypoxic and hypercapnic rats

Fonction rénale et hémodynamique intrarénale chez des rats soumis à une hypoxie et une hypercapnie aiguës. Les effets de l'hypoxie et de l'hypercapnie aiguës sur le rein ont été étudiés chez des rats, anesthésiés et ventilés mécaniquement, au moyen de la distribution de microsphères, des courbes de lavage des gaz inertes et des clearances. L'hypoxie modérée (Po2 moyenne de 48 mm Hg) ne modifie pas significativement la diurèse, la filtration glomérulaire et l'excrétion du sodium. Du fait d'une diminution de la résistance vasculaire (R) de 40,1 à 31,8 mm Hg · ml­1 · min le débit sanguin moyen n'a pas varié malgré une chute significative de la pression artérielle moyenne. Ces modifications hypoxiques de R n'ont été accompagnées par des modifications significatives de la distribution du débit sanguin rénal (IDBF). Dans l'hypoxie sévère (Po2 < 45 mm Hg) avec oligurie et hypotension artérielle importante, R était le plus bas de tous les groupes (28,8 mm Hg·ml­1·min). L'hypercapnie ne modifie pas significativement les paramètres d'excrétion, bien qu'une augmentation de R (sans modification d'IDBF) en même temps qu'une diminution de MAP détermine une chute du débit sanguin moyen. De ces résultats nous concluons que: 1) chez le rat anesthésié l'hypoxie aigue détermine une modification significative de l'hémodynamique intrarénale sans modification de la fonction excrétoire, 2) la vasodilatation hypoxique persiste dans l'hypotension sévère avec oligurie et anurie, 3) dans l'hypoxie et l'hypercapnie aiguës les modifications du débit sanguin rénal et des résistances vasculaires ne sont pas accompagnées par des modifications significatives d'IDBF

Effect of electron-phonon interaction on the formation of one-dimensional electronic states in coupled Cl vacancies

The formation of extended electron states in one-dimensional nanostructures is of key importance for the function of molecular electronics devices. Here we study the effects of strong electron-phonon interaction on the formation of extended electronic states in intentionally created Cl vacancy pairs and chains in a NaCl bilayer on Cu(111). The interaction between the vacancies was tailored by fabricating vacancy pairs and chains of different orientation and separation with atomic precision using vertical manipulation. Small separation of divacancies led to the formation of symmetric and antisymmetric vacancy states and localized interface-states. By scanning tunneling spectroscopy (STS) we measured their energy splitting and broadening as a function of the inter-vacancy separation. Unexpectedly, the energy splitting between the vacancy states is enlarged by level repulsion resulting from phonon dressing of the electronic states, as evidenced by theory. Already for a few coupled vacancies we observe an emerging band structure of the defect band.Comment: 9 pages, 4 figure

Electrically driven photon emission from individual atomic defects in monolayer WS2.

Quantum dot-like single-photon sources in transition metal dichalcogenides (TMDs) exhibit appealing quantum optical properties but lack a well-defined atomic structure and are subject to large spectral variability. Here, we demonstrate electrically stimulated photon emission from individual atomic defects in monolayer WS2 and directly correlate the emission with the local atomic and electronic structure. Radiative transitions are locally excited by sequential inelastic electron tunneling from a metallic tip into selected discrete defect states in the WS2 bandgap. Coupling to the optical far field is mediated by tip plasmons, which transduce the excess energy into a single photon. The applied tip-sample voltage determines the transition energy. Atomically resolved emission maps of individual point defects closely resemble electronic defect orbitals, the final states of the optical transitions. Inelastic charge carrier injection into localized defect states of two-dimensional materials provides a powerful platform for electrically driven, broadly tunable, atomic-scale single-photon sources

Identifying substitutional oxygen as a prolific point defect in monolayer transition metal dichalcogenides with experiment and theory

Chalcogen vacancies are considered to be the most abundant point defects in two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors, and predicted to result in deep in-gap states (IGS). As a result, important features in the optical response of 2D-TMDs have typically been attributed to chalcogen vacancies, with indirect support from Transmission Electron Microscopy (TEM) and Scanning Tunneling Microscopy (STM) images. However, TEM imaging measurements do not provide direct access to the electronic structure of individual defects; and while Scanning Tunneling Spectroscopy (STS) is a direct probe of local electronic structure, the interpretation of the chemical nature of atomically-resolved STM images of point defects in 2D-TMDs can be ambiguous. As a result, the assignment of point defects as vacancies or substitutional atoms of different kinds in 2D-TMDs, and their influence on their electronic properties, has been inconsistent and lacks consensus. Here, we combine low-temperature non-contact atomic force microscopy (nc-AFM), STS, and state-of-the-art ab initio density functional theory (DFT) and GW calculations to determine both the structure and electronic properties of the most abundant individual chalcogen-site defects common to 2D-TMDs. Surprisingly, we observe no IGS for any of the chalcogen defects probed. Our results and analysis strongly suggest that the common chalcogen defects in our 2D-TMDs, prepared and measured in standard environments, are substitutional oxygen rather than vacancies

Thrombus Aspiration in ThrOmbus containing culpRiT lesions in Non-ST-Elevation Myocardial Infarction (TATORT-NSTEMI): study protocol for a randomized controlled trial

Current guidelines recommend thrombus aspiration in patients with ST-elevation myocardial infarction (STEMI); however, there are insufficient data to unequivocally support thrombectomy in patients with non-STEMI (NSTEMI).Methods/Design The TATORT-NSTEMI (Thrombus Aspiration in ThrOmbus containing culpRiT lesions in Non-ST-Elevation Myocardial Infarction) trial is a prospective, controlled, multicenter, randomized, open-label trial enrolling 460 patients. The hypothesis is that, against a background of early revascularization, adjunctive thrombectomy leads to less microvascular obstruction (MO) compared with conventional percutaneous coronary intervention (PCI) alone, as assessed by cardiac magnetic resonance imaging (CMR) in patients with NSTEMI. Patients will be randomized in a 1:1 fashion to one of the two treatment arms. The primary endpoint is the extent of late MO assessed by CMR. Secondary endpoints include early MO, infarct size, and myocardial salvage assessed by CMR as well as enzymatic infarct size and angiographic parameters, such as thrombolysis in myocardial infarction flow post-PCI and myocardial blush grade. Furthermore, clinical endpoints including death, myocardial re-infarction, target vessel revascularization, and new congestive heart failure will be recorded at 6 and 12 months. Safety will be assessed by the incidence of bleeding and stroke.Summary The TATORT-NSTEMI trial has been designed to test the hypothesis that thrombectomy will improve myocardial perfusion in patients with NSTEMI and relevant thrombus burden in the culprit vessel reperfused by early PCI

Thrombus Aspiration in ThrOmbus containing culpRiT lesions in Non-ST-Elevation Myocardial Infarction (TATORT-NSTEMI): study protocol for a randomized controlled trial

Current guidelines recommend thrombus aspiration in patients with ST-elevation myocardial infarction (STEMI); however, there are insufficient data to unequivocally support thrombectomy in patients with non-STEMI (NSTEMI).Methods/Design The TATORT-NSTEMI (Thrombus Aspiration in ThrOmbus containing culpRiT lesions in Non-ST-Elevation Myocardial Infarction) trial is a prospective, controlled, multicenter, randomized, open-label trial enrolling 460 patients. The hypothesis is that, against a background of early revascularization, adjunctive thrombectomy leads to less microvascular obstruction (MO) compared with conventional percutaneous coronary intervention (PCI) alone, as assessed by cardiac magnetic resonance imaging (CMR) in patients with NSTEMI. Patients will be randomized in a 1:1 fashion to one of the two treatment arms. The primary endpoint is the extent of late MO assessed by CMR. Secondary endpoints include early MO, infarct size, and myocardial salvage assessed by CMR as well as enzymatic infarct size and angiographic parameters, such as thrombolysis in myocardial infarction flow post-PCI and myocardial blush grade. Furthermore, clinical endpoints including death, myocardial re-infarction, target vessel revascularization, and new congestive heart failure will be recorded at 6 and 12 months. Safety will be assessed by the incidence of bleeding and stroke.Summary The TATORT-NSTEMI trial has been designed to test the hypothesis that thrombectomy will improve myocardial perfusion in patients with NSTEMI and relevant thrombus burden in the culprit vessel reperfused by early PCI

Silicon photonics-based laser Doppler vibrometer array for carotid-femoral pulse wave velocity (PWV) measurement

Pulse wave velocity (PWV) is a reference measure for aortic stiffness, itself an important biomarker of cardiovascular risk. To enable low-cost and easy-to-use PWV measurement devices that can be used in routine clinical practice, we have designed several handheld PWV sensors using miniaturized laser Doppler vibrometer (LDV) arrays in a silicon photonics platform. The LDV-based PWV sensor design and the signal processing protocol to obtain pulse transit time (PTT) and carotid-femoral PWV in a feasibility study in humans, are described in this paper. Compared with a commercial reference PWV measurement system, measuring arterial pressure waveforms by applanation tonometry, LDV-based displacement signals resulted in more complex signals. However, we have shown that it is possible to identify reliable fiducial points for PTT calculation using the maximum of the 2nd derivative algorithm in LDV-based signals, comparable to those obtained by the reference technique, applanation tonometry. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Are Chinese consumers at risk due to exposure to metals in crayfish? A bioaccessibility-adjusted probabilistic risk assessment

Freshwater crayfish, the world's third largest crustacean species, has been reported to accumulate high levels of metals, while the current knowledge of potential risk associated with crayfish consumption lags behind that of finfish. We provide the first estimate of human health risk associated with crayfish (Procambarus clarkii) consumption in China, the world's largest producer and consumer of crayfish. We performed Monte Carlo Simulation on a standard risk model parameterized with local data on metal concentrations, bioaccessibility (phi), crayfish consumption rate, and consumer body mass. Bioaccessibility of metals in crayfish was found to be variable (68-95%) and metal-specific, suggesting a potential influence of metal bioaccessibility on effective metal intake. However, sensitivity analysis suggested risk of metals via crayfish consumption was predominantly explained by consumption rate (explaining >92% of total risk estimate variability), rather than metals concentration, bioaccessibility, or body mass. Mean metal concentrations (As, Cd, Cu, Ni, Pb, Se and Zn) in surveyed crayfish samples from 12 provinces in China conformed to national safety standards. However, risk calculation of phi-modified hazard quotient (HQ) and hazard index (HI) suggested that crayfish metals may pose a health risk for very high rate consumers, with a HI of over 24 for the highest rate consumers. Additionally, the phi-modified increased lifetime risk (ILTR) for carcinogenic effects due to the presence of As was above the acceptable level (10(-5)) for both the median (ILTR = 2.5 x 10(-5)) and 90th percentile (ILTR = 1.8 x 10(-4)), highlighting the relatively high risk of As in crayfish. Our results suggest a need to consider crayfish when assessing human dietary exposure to metals and associated health risks, especially for high crayfish-consuming populations, such as in China, USA and Sweden.HZ by the National Natural Science Foundation of China (41273087). LN was supported by European Union Marie Curie Actions, Grant FP People 2010 “IRSES Electroacross” and BG by the SAGE-IGERT Fellowship (US National Science Foundation)